For days, the first-anniversary protests in Ferguson, Mo., were enflamed by charges that police there had shot an unarmed protester. Then video surfaced showing Tyrone Harris brandishing a gun during Sunday’s commemoration of Michael Brown’s death.

It’s not as simple as the Black Lives Matter movement would have the world believe.

Of course, video has exposed some horrifically bad cops, too.

Cellphone footage caught a North Charleston, SC, officer shooting a fleeing man in the back — and then covering up the scene. A dashboard cam exposed a University of Cincinnati cop’s lies about his fatal shooting of a motorist. Both men are charged with murder.

With more cameras everywhere, it’s easier to expose bad police and phony “victims.”

Yet even raw footage from a single source doesn’t always tell the whole story.

Here in New York, the famous video of the fatal Eric Garner incident struck many as damning. Yet the grand jurors who saw video from other sources, with different angles — and heard hours of eyewitness testimony — reached a different conclusion.

Many think that was an injustice. Seeing the grand-jury evidence might prove them wrong — but, unfortunately, the courts insist the evidence remain sealed.

The Post argued for release of that evidence, and we suggest it’s time for careful thought to changing the rules for the future.

In an age when the public will inevitably see far more partial evidence in controversial cases, there’s a strong argument for sharing all the facts.